Stepper用于增加和减少值，由两个按钮组成，变化的速率取决于用户按下控件的持续时间。
class UIStepper : UIControl
无涯教程可以设置UIStepper的最大值和最小值；但是，最大值将始终大于最小值。如果最大值小于最小值，则这两个值相等。
在此示例中，无涯教程正在使用标签和Uistepper。这是一个简单的例子，其中标签的文本相当于步进值的变化。
ViewController.swift
import UIKit
class ViewController: UIViewController {
</span><span class="lit">@IBOutlet</span><span class="pln"> weak </span><span class="kwd">var</span><span class="pln"> valueLbl</span><span class="pun">:</span><span class="pln"> </span><span class="typ">UILabel</span><span class="pun">!</span><span class="pln">
</span><span class="lit">@IBOutlet</span><span class="pln"> weak </span><span class="kwd">var</span><span class="pln"> stepper</span><span class="pun">:</span><span class="pln"> </span><span class="typ">UIStepper</span><span class="pun">!</span><span class="pln">
</span><span class="kwd">override</span><span class="pln"> func viewDidLoad</span><span class="pun">()</span><span class="pln"> </span><span class="pun">{</span><span class="pln">
</span><span class="kwd">super</span><span class="pun">.</span><span class="pln">viewDidLoad</span><span class="pun">()</span><span class="pln">
</span><span class="com">//加载视图后进行任何其他设置。</span><span class="pln">
stepper</span><span class="pun">.</span><span class="pln">autorepeat </span><span class="pun">=</span><span class="pln"> </span><span class="kwd">true</span><span class="pln">
stepper</span><span class="pun">.</span><span class="pln">isContinuous </span><span class="pun">=</span><span class="pln"> </span><span class="kwd">true</span><span class="pln">
valueLbl</span><span class="pun">.</span><span class="pln">text </span><span class="pun">=</span><span class="pln"> stepper</span><span class="pun">.</span><span class="kwd">value</span><span class="pun">.</span><span class="pln">description
stepper</span><span class="pun">.</span><span class="pln">maximumValue </span><span class="pun">=</span><span class="pln"> </span><span class="lit">20</span><span class="pln">
stepper</span><span class="pun">.</span><span class="pln">minimumValue </span><span class="pun">=</span><span class="pln"> </span><span class="pun">-</span><span class="lit">20</span><span class="pln">
</span><span class="pun">}</span><span class="pln">
</span><span class="lit">@IBAction</span><span class="pln"> func stepperValueChanged</span><span class="pun">(</span><span class="pln">_ sender</span><span class="pun">:</span><span class="pln"> </span><span class="typ">UIStepper</span><span class="pun">)</span><span class="pln"> </span><span class="pun">{</span><span class="pln">
valueLbl</span><span class="pun">.</span><span class="pln">text </span><span class="pun">=</span><span class="pln"> sender</span><span class="pun">.</span><span class="kwd">value</span><span class="pun">.</span><span class="pln">description
</span><span class="pun">}</span><span class="pln">
}
输出:
